1. Field of the Invention
This invention relates to a breast prosthesis for implantation beneath the skin, and more specifically, to the use of a foam body for such a prosthesis.
2. Definitions
The term "foam insert" as used herein means a unitary foam body having both open-cell and closed cell characteristics.
3. Description of the Prior Art
Breast implants are well known in the art. Silicone gel-filled implants useful for breast augmentation or reconstruction were introduced as early as 1963. Early embodiments provided a prosthesis with a peripheral seam, a thick shell, a heavy gel filling and a dacron patch on the posterior surface for affixing the implant onto the chest wall. Similar gel-filled implants have substantially dominated the reconstructive market until 1990.
There has been a renewed interest during the last 3 years in saline-filled breast implants. Saline has the advantage that in the event that the shell (which contains the saline) is ruptured, as for example due to a traumatic injury, the release of saline from the interior of the prosthesis is relatively safe to the person hosting the prosthesis. With this belief has come a resurgence in the development of saline-filled products. Notwithstanding the foregoing alleged advantage, saline-filled products have long been plagued with the problem of wrinkling which may occur when an elastic bag containing saline is anchored to the chest wall. When the patient is the upright position, the saline, being denser than the surrounding breast tissue travels under gravity towards the bottom of the envelope or shell and may cause wrinkling or creases to form in the superior portion, giving it an unnatural look. Moreover, "wave action", or "sloshing" of the saline within the implant occurs which is aesthetically undesirable. To overcome the potential problems of sloshing, wrinkling, and, in general, to improve the overall acceptability of a saline-filled implant, researchers have tried inserting various sorts of fillers into shells, which fillers, together with saline, provide a superior product that more closely resembles the density and hydrostatic properties of breast tissue. Thus, multilumen devices have been employed to provide a lubricious layer adjacent to the inner periphery of the shell and a second inner lumen containing saline therein. Others, such as U.S. Pat. No. 5,171,269 to Bark, describe inserting a fibrous material within the shell to impede the movement of saline in the interior volume of the shell and provide some structural integrity to the breast prosthesis. To date, none of the filler materials for saline implants have proven as natural feeling as the silicone gel-filled implants they are rapidly replacing.